1. Field of the Invention
The present invention is directed to an aircraft course deviation indicator. More particularly, the present invention is directed to an aircraft course deviation indicator having improved flags for indicating when the course deviation indicator is providing a reading that is known to be in error.
2. Description of the Related Art
Aircraft course deviation indicators are well known. A course deviation indicator provides a display for indicating to a pilot or navigator of an aircraft any deviation between the actual flight path of the aircraft and a pre-established course. Conventional course deviation indicators utilize a vertical deviation bar which moves upwardly or downwardly from a center position as the aircraft correspondingly deviates from the desired course. Additionally, the course deviation indicator utilizes a lateral deviation bar which moves laterally as the aircraft correspondingly deviates from a desired lateral course. Inputs to the course deviation indicator traditionally come from a glide slope and VHF NAV unit, but are increasingly being provided from a GPS unit.
Additionally, many traditional course deviation indicators utilize a pair of flags to indicate to the pilot or navigator that the course deviation indicator is not providing valid or accurate data. In this regard, FIG. 1, described in greater detail below, illustrates a conventional prior art course deviation indicator. As illustrated, in the prior art design, a vertical flag is visually presented on a display of the course deviation indicator when a determination is made that the vertical deviation bar is providing inaccurate information and, thus, should be ignored. Similarly, a lateral flag is visually displayed, in the prior art design, when a determination is made that the lateral deviation bar is providing inaccurate information, and should thus be ignored.
The present invention is an improvement over conventional prior art course deviation indicators. Particularly, the present invention provides a unique course deviation indicator for indicating to an aircraft pilot or navigator that a display of the course deviation indicator is not providing accurate information. More particularly, the present invention provides a course deviation indicator which more readily indicates to a pilot or navigator the nature of such an inaccuracy.
The present invention is a course deviation indicator having a display that utilizes a vertical deviation bar and a lateral deviation bar, each of which moves corresponding to a deviation in the actual path of an aircraft from an intended course. In accordance with an aspect of the invention, a first indicator, sometimes referred to herein as a vertical flag, is provided on the display at a location proximate an outer end of the vertical deviation bar when the vertical deviation bar is located at a center position. In particular, the first indicator (e.g., the vertical flag) is a bi-directional arrow oriented in a vertical orientation with respect to the display. Additionally, a second indicator, sometimes referred to herein as a lateral flag, is positioned on the display at a location proximate an outer end of the lateral deviation bar when the lateral deviation bar is at a centered position. Like the vertical flag, the lateral flag is in the form of a bi-directional arrow. However, unlike the vertical flag, the lateral flag is presented in a lateral orientation with respect to the display. In a preferred embodiment, the coloration or color scheme of each of the vertical flag and lateral flag are such that each is colored differently than the remainder of the display in such a way as to command immediate attention. Specifically, in one particularly preferred embodiment of the invention, each flag comprises a red arrow or, alternatively, a black arrow on a red background.
As will be understood, the vertical flag is displayed visually only when a determination is made that the vertical deviation bar is illustrating inaccurate information, such as is determined in a conventional manner. Similarly, the lateral flag is visually displayed only when a determination is made, in a conventional manner, that the lateral deviation bar is providing inaccurate information. The visual display of the unique flags is accomplished in a conventional manner, such as by mechanical positioning of the flag into a visible position or window within the display. Additionally, when a determination to display a flag is made and the appropriate, corresponding flag is displayed, the deviation bar with which the displayed flag is associated is automatically moved back to centered position.
Additionally, in an alternate embodiment of the present invention, only one deviation bar and associated flag are utilized. For example, the device of the present invention may utilize only a lateral deviation bar and associated flag. Such a device is particularly useful for marine navigation, in which altitude is not an issue. In an aircraft, such a device might be used for en-route navigation if no vertical course guidance is provided.
Additionally, in still yet another alternate embodiment of the invention, a display is an LCD display. In such an embodiment, a display controller draws the lateral flag and/or vertical flag directly on the LCD display, as needed.